Hot-filament rectifier



Dec. 24, 1929, E. w. BREISCH 0,

HOT FILAMENT RECTIFIER Original Filed Nov. 5. 1920 I 6 I 7 i; 47 I AZ J9/0 WlTNES SES: {NVENTOR 4.66 44M fi/yzr W fira/sz W BY MW W.

ATTORNEY Patented Dec. 24, 1929 UNITED STATES PATENT. OFFICE EDGAR W.BREIS CH, OE EDGE'WOOD, PENN SYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC8t MANUFACTURING COMPI sNY, A CORPORATION PENNSYLVANIA I Ho'r-rILAMEn'rRECTIFIER Application filed November 5, 1920, Serial No. 422,019.Renewed October 11, 1923.

- This invention relates to hot-filament rectifiers and, in particular,to means for increasing the rating and the life of such rectifiers. I

In the operation of a hot-filamentrectifier bulb, the current passesfrom the bulb anode to the filament and then, combining with thefilament current, increases thetemp'erature of the filament. As thefilament temperature determines the rating of the bulb, any method whichwill allow a greater rectified'current Without an increased heating ofthe filament will increase the capacity of the bulb or give a longerlife at the same rating.

My invention relates particularly to filamentary rectifiers of the typewherein the 'fila- 'ment temperature tends 'to follow the wave form ofthe current traversing the filament. Where the filament of the rectifieris ener- 2 gized from a small auxiliary-coil on an alternating currenttransformer, and the load current is in phase with the heating current,the load current passes from'the anode to the filament and therecombines with the filament I current to increase the temperature of thefilament, particularly at the peak of the current wave.

The main object of my invention, therefore,

is to provide means whereby the rectified our- 30 rent and the filamentcurrent may be so dis: placedin time-phasethat, when the rectifiedcurrent is maximum thefilament current is minimum. This may be done bymeans of an internal reactance 1n the transformer, or

35 by a separatereactance, so adjusted as to give the proper phaseangle.

The single figure of the drawing is a sche-Y matic diagram ofconnections, showing a pre ferred form of transformer;

o i The alternating-current supply -is fed throu h leads 1 and 2 to theprimary coils 3, 3 o a transformer 4. The secondary coils 5,5 areconnected together and a mldpoint 6 of such connection is connected tothe negative terminal of the battery7.'. The coils 5, 5 have their outerterminals 7 and 8 connected respectively, to the anodes 9 and 10 of thebulbs 11 and 12. The filaments 13, 13 of the bulbs are energized,respectively, from auxillo iary coils- 15, 15 of the "transformer. The

positiveterminal of the battery 7' is connect: ed to the filaments 13,13through a junction point 14 that. connected also to the common terminal16 of the coils 15, 15. The C0llS 5, 5 and 3, 3 may be separatedbyducting material. As shown, the auxiliary coils 15 are wound over theprimary coils 3 in order to ensure good regulation therein,

In operation, the charging current for the 155 means of washers 17 ofany suitable non-con- I battery? divides between thesecondary coils 5, 5and the bulbs 11, 12, as iswell understood. That is, during one halfcycle, when the terminal? is positive, the current flows through bulb 11to the positive terminalof the battery 7 and thence backto thelneutralpoint 6 of. the secondary. In like manner;

when the tei'1'nina'l18 is positive'thecurrent flows through bulb 12 tothe positivetermisecondary winding '5-on a portion of the I transformercore, which is separated from the primary winding 3 by a considerablein- I tervening space and by the, non-magnetic spacers 17, a substantiale to intervene between the primary and load secondary windings. Asawell-known con-g comltant of such a leakage flux" between transformerwindin s, an internal impedance effect is produced w ereby the secondaryhas i a phase displacement with. respect to the primary, the amount ofdisplacement being dependent upon load current in the secondary. Sincethe filament-heating current is very nearly in phase with the primarycurrent, it will be seen that the rectified current passing fromanode'to filament will not reach its maximum or peak value at the sametime as the heating current of the filament. In this manner, thefilament may be made from a I much finer wire than in other designs.

There are various ways of obtaining the desired result, with thereactance either internal or external to the transformer, and

my invention is not to be construed as being limited to the exactconstruction shown.

I claim as my invention "1L The combinatiomwith a transformer comprisinga. primary winding, a main secondar Winding and an auxiliary second- MyWin ing, of a filamentary rectifier bulb 'having its filament connectedto said a'uX- iliary Winding and its oad circuit-connected" I to saidmain secondar winding, and meansfor providing a path r'considerably moreleakage between said piimary Winding and said main secondary Windingthan between said. primary Winding and said auxiliary winding 2. Thecombination with a rectifyingde Vice having a heated filament, of a'transformer comprising acore having t'woserially connected magnetizableportions'and'means for providing aleakage flux between said-1 portions,coils .on both of said portions, a

supply circuitfc'onnected across coils mainly on one of said portions, afilament-energizing circuit connected across coils superposed on saidlast mentioned .coils and a load circuit 4 including said rectifyingdevice and' con- 2a nected across -coils -mainly on the other of;

' said portions. v

' 3. The combination with an electrical-discharge device havinga heatedcathode and an anode, of a transformer comprising a core havingtwoserially-related magnetizableportions' and means "for providinga'leakage flux between-saidportions,coils on both. of said portions, aload circuit includingisaidanode and cathode and, connectedacrosswindings on one of said portions,- a filament-energizing circuitconnected across windings on the other i of said'portions, and a. supplcircuit connected'across 'windings'on the latter portion. 4. Incombination with an electrical-dis.

1 no charge device having "afcathode adapted to be-heated and an anode asupply transformer fhaving'ai r'irnaryw'indmg, a secondary windpingclose y coupled magnetically with said primary for he'ating said cathodeand another 4 secondary,windingsubstantially less closely .coupledflmagnetically with said primary winding for'producin current flowbetween said anode and-catho e.' i. v I 3 y In testimony whereof, I havehereunto subscribed my name this 27th day o-f October;

v1920. EDGAR W. BREISGH;

